1. Technical Field
The invention relates to electro-mechanical actuators, methods of calibrating electro-mechanical actuators, and method of operating electro-mechanical actuators.
2. Discussion of Related Art
This section introduces aspects that may facilitate a better understanding of the invention. Accordingly, the statements of this section are to be read in that light. The statements of this section are not admissions about what is in the prior art or about what is not in the prior art.
Many electro-mechanical actuators incorporate a comb drive. Herein, a comb drive refers to a capacitor having two capacitor plates, wherein each capacitor plate has teeth capable of inter-digitating with teeth of the other capacitor plate and, at least, one capacitor plate can move relative to the other capacitor plate. The teeth of the capacitor plates of a comb drive will increase the surface area of the capacitor thereby increasing the associated capacitance. Due to the increased surface area, a comb drive often will be able to produce a larger electrostatic force between its two capacitor plates than a planar capacitor having comparable overall dimensions but lacking capacitor plates with teeth.
In an electro-mechanical actuator that is based on comb drives, the mobile capacitor plates of the comb drives may be physically fixed to a structure so that the movement of the mobile capacitor plates displaces and/or reorients the structure. Then, the control voltages applied to the comb drives can be used to both displace the mobile capacitor plates of the comb drives and displace and/or reorient the structure physically fixed to those mobile capacitor plates.